| 1 | /// [`Records`] extension which guarantees the amount of rows. |
| 2 | /// |
| 3 | /// [`Records`]: crate::records::Records |
| 4 | pub trait ExactRecords { |
| 5 | /// Returns an exact amount of rows in records. |
| 6 | /// |
| 7 | /// It must be guaranteed that an iterator will yield this amount. |
| 8 | fn count_rows(&self) -> usize; |
| 9 | } |
| 10 | |
| 11 | impl<T> ExactRecords for &T |
| 12 | where |
| 13 | T: ExactRecords, |
| 14 | { |
| 15 | fn count_rows(&self) -> usize { |
| 16 | T::count_rows(self) |
| 17 | } |
| 18 | } |
| 19 | |
| 20 | #[cfg (feature = "std" )] |
| 21 | impl<T> ExactRecords for Vec<T> { |
| 22 | fn count_rows(&self) -> usize { |
| 23 | self.len() |
| 24 | } |
| 25 | } |
| 26 | |
| 27 | impl<T> ExactRecords for [T] { |
| 28 | fn count_rows(&self) -> usize { |
| 29 | self.len() |
| 30 | } |
| 31 | } |
| 32 | |